CZ301556B6 - Method of authorizing a key and lock device and key and lock device per se - Google Patents

Abstract

In the present invention, there is described a method of authorizing a key and lock device comprising the steps of carrying out an authentication process between a first user device and a first system device using a first encryption key, and in case said authentication process was successful, carrying out a software operation by said first system device, by which software operation said first encryption key stored in said first user device is replaced by a second encryption key. There is also described a key and lock device comprising at least one system device (SD1 through SD3) having electronic circuits having an electronic memory adapted for storing a permanent electronic code, a computer program software adapted to change a variable electronic encryption key of a user device from a first to a second encryption key as a result of a successful authentication process carried out between a lock or user key having a stored variable electronic encryption key, and a system device having an identical encryption key as said lock or user key.

Description

A method of authorizing user equipment of a key and lock system and a key and lock system

ObiasUssímiky

The present invention relates to a method of authorizing user equipment of a key and lock system, wherein the user equipment is a user key or master key system lock, the method comprising the steps of: providing a user equipment having electronic circuitry, creating a first system device having electronic circuitry and in the first level of the key and lock system, and storing the first encryption key in the first user equipment and the first system device. The present invention relates to a key and lock system comprising: a plurality of user equipments comprising: a plurality of user keys having electronic circuitry comprising an electronic memory adapted to store a variable electronic coding key, and a plurality of locks having electronic circuitry including an electronic memory adapted to store a variable electronic the key and the user key and the lock are operable together only when identical key keys are stored in the user key and the lock.

BACKGROUND OF THE INVENTION

Electromechanical locking systems are already known in which keys are assigned to different users in a conventional manner similar to the way keys are distributed in a mechanical locking system. However, this distribution is difficult to perform and it is very difficult to distribute new keys. Also, there is always the risk that an unauthorized person will acquire a system key, which then leads to security risks and the like.

Another problem is that electronic codes can be copied, for example by "recording" the code through a reader, and copies can be present in the key system without the system owner being aware of it.

Yet another problem of the prior art is that the key blanks can be used by anyone, which entails security risks.

US Patent Document US 6,005,487 (Hyatt, Jr. et al.) Discloses an electronic security system including an electronic locking mechanism and an electronic key. In order to avoid the need for expensive key renewal (replacement) in case of key loss, or to eliminate the possibility of internal fraud and theft, the system of this US 6,005,487 allows the key or lock identification code to be changed. The aforementioned problems of the prior art are not solved by this system.

It is an object of the present invention to provide an electromechanical key and lock device of the initially mentioned type and used in a system in which the distribution and authorization of keys and locks between the manufacturer, the distributor and the customer have a high level of security.

Another object of the present invention is to provide an electromechanical lock device in which key distribution and authorization is facilitated.

Another object of the invention is to provide a key device that is difficult to copy without the knowledge of the system owner.

Another object of the invention is to provide a key blank that is limited as far as its use is limited to a limited number of distributors.

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Another object of the invention is to provide easy and safe addition of keys and locks to the locking system.

Another object of the invention is to provide a method and system for storing and displaying master key system information in a secure manner.

Another object of the invention is to provide a method and system for exchanging information between a manufacturer, a distributor and an end user of a key and lock device.

The essence of the invention

The invention is based on the discovery that the above-mentioned problems of the prior art can be solved by creating and exchanging electronic codes in keys and locks, these codes being used for coded communication between keys and locks and between the various parties involved in creating and maintaining the lock. system.

According to the present invention, there is provided a method of the type mentioned in the introduction, comprising the steps of performing an authentication process between a user equipment and a first system device using a first encryption key, and, if the authentication process was successful, performing a software operation a first system device in which the first encryption key stored in the user equipment is replaced by a second encryption key, wherein the second encryption key is stored in the second system devices and other user devices used in the second level of the key and lock system, thereby achieving the user equipment is operable with second system and other user equipment.

Preferably, during the step of replacing the first coding key stored in the user equipment, the second coding key is supplied by the first system device.

Preferably, during the step of replacing the first encryption key stored in the user equipment, the second encryption key is delivered via a computer.

The method of the invention preferably further comprises the additional step of delivering a second encryption key to the computer via a network such as a local area network and a public telephone network.

Preferably, the first system device is a master key system key.

Preferably, the user equipment is a master key system user key.

Preferably, the user equipment is a master key system lock.

Preferably, the electronic coding keys are illegible from the outside of said electronic circuits.

According to the invention, there is further provided a key and lock system of the type mentioned above, comprising at least one system device having electronic circuitry comprising an electronic memory adapted to store a permanent electronic encryption key, and computer program software adapted to change a variable electronic a user equipment coding key from the first coding key to the second coding key as a result of a successful authentication process performed between a lock or user key having a stored variable electronic coding key and a system device having the same coding key as said lock or user key; stored in the second system devices and user devices used in the second level of the key and lock system, thereby being user devices operational with these second system and user devices.

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In the following description, the present invention will be described in more detail by way of example embodiments with reference to the accompanying drawings.

Summary of drawings in drawings io

Giant. 1 is a diagram for explaining the basic idea of the present invention;

Giant. 2 shows an overall view of a hierarchical locking system with key and lock devices according to the invention;

Giant. 3a shows information elements of a key device according to the invention;

Giant. 3b shows information elements of a lock device according to the invention;

Giant. 4 illustrates an example of the information flow in the system shown in FIG. 2;

Giant. 5 shows an overview of the electronic key coding elements in the key and lock device of the invention;

Giant. 6 is a diagram illustrating the security of data exchange between a manufacturer, a distributor and a customer;

Giant. 7 shows an overview of the coding of the database used according to the invention; and

Giant. 8 illustrates an example of a database file encoding table.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the present invention will now be described. For a clear description, the term 'key' will be made clear by adding 'physical' if the word key is meant to refer to a physical key, that is, a mechanical key adapted for use with a lock, or by adding 'electronic' or 'coding', if the word key is to denote an electronic key, such as an encryption key.

In addition, the prefix "e" is used to denote the encoded information and the prefix "d" to denote the decoded information. The encoding key used follows this prefix. For example, the term eKx (File1) refers to File 1 encoded with the encoding key "Kx".

In this description, the term "device" is sometimes used. The device in the context of the present invention is to be interpreted as a key or lock device.

First, the basic idea of the present invention will be explained with reference to Fig. 1, which illustrates a diagram of the various parts of the locking system according to the invention. Three 'levels' of the locking system are shown, labeled 'manufacturer', 'locksmith' and 'MKS user' respectively. In each level, the system device and possibly the computer is in one or more levels.

At various levels, user devices such as keys and / or locks are shown. However, "User Device 1" is the same device at all levels, although in different "modes".

Each system and user device has a hidden encryption key, "key", "key2", and so on. These encryption keys are used for authentication processes between system and user devices as well as between different user devices, i.e., between end-user keys and locks. The encryption keys stored in the user equipment are variable, that is, they can be changed by the system device, optionally in conjunction with computer software, as will be explained in the following description.

Thus, for example, the user equipment UD1 stored at level 1, for example, has a coding key of the "key" during the production of the key blank. When the user equipment 1 is to be passed to level 2, an authentication process is initiated between the SD1 system device and the UD1 user equipment using the encryption key "keys". If this verification process is successful, the "keys"

The memory is stored in the user equipment and is replaced by the coding key "key2 ^M" and the process is terminated. The new encryption key "key2" can be supplied either by the system device itself or possibly by a CI computer. No other successful authentication process can subsequently be performed at this level between the respective user equipment and the system device because the encryption keys do not match.

The user equipment can now be safely delivered to level 2, the "locksmith" level, because a potential cheating participant that intercepts the user equipment will not be able to use the user equipment without knowing the hidden encryption key stored in the appliance, i.e. the encryption key "key2".

At level 2, the corresponding procedure is performed as in level 1 before the user equipment is delivered to the end user, that is, the coding key "key2" stored in the user equipment is replaced by the coding key "key3" via the SD2 system device; in cooperation with the C2 computer.

A user equipment that reaches the end user level, i.e., level 3, cannot be used until it has been authorized through the SD3 system device in the same way as in level 2. This means that the coding key "key3" is replaced with the coding key "key4" after a successful verification process using the "key3" encryption key. All user equipment, i.e. all keys and locks of the master key system, must go through this process before they can be used. This also means that all "activated" user devices have a "key 4" encryption key stored therein and can therefore perform successful authentication processes with each other. This ensures complete security when distributing keys or locks to the end user master key system.

The locking system comprising the key and lock device of the present invention will now be described in detail with reference to Fig. 2, which illustrates a typical distribution of hardware and software tools between different levels of the hierarchy, more specifically between customer 100, distri30 butor 200 and manufacturer 300.

User keys

In the customer system 100 there are several user keys 101 adapted for use with a plurality of locks 20. Together, user keys and locks form a master key system (MKS). Each key has a unique individual electronic code controlling its function. The electronic code is divided into different segments for use by manufacturers, distributors and customers. A public (open) segment is created for open (public) information, and a secret segment for secret information is also created. The segments are further divided into various elements or items of the electronic code. The electronic key code is further discussed below in connection with the description of protected modes. Programming and authorization key

At least one customer, programming and authorization key (C-key) 102 exists for the customer system 100. C-keys together with D-keys and M-keys (see description below) will also be referred to herein as system keys (SYS-keys) ).

Custom programming box

On the customer's side there is a programming box 106 adapted for connection to a computer (PC) 104 via, for example, a serial interface. This programming box includes a static reader 107 and is used for programming in a customer system. The static reader 107 is a key reader without a locking mechanism and thus includes electronic circuits, and so on, for reading and programming the key.

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Although the illustration shows the customer programming box 106. this programming box 106 can be omitted in very small locking systems.

Customer software

The customer has access to a personal computer 104 operating with the customer administration software (C-software) only with open (public) system information. The C-software thus keeps track of which keys are authorized in which locks of the respective master key system in the so-called lock map. However, the secret identities (see below) of all keys are stored in coded form that can only be read by the system key. Reseller Authorization Key

For the distributor of the locking system, which may be, for example, a locksmith, an author 15 start key (D-key) 202 of the distributor is provided.

Distributor programming box

On the distributor side there is also a programming box 206 adapted for connection to a computer (PC).

204 via, for example, a serial interface. This programming box 206 may be the same or similar to the box described in connection with the customer system 100.

Distributor software

The distributor has special computer software (D-software) for the personal computer 204. The D-software includes an open (public) portion for displaying open system information and for constructing changes, and so on. This D-software also contains a secret section containing authorization codes and secret keywords used in the system. The D-software also supports encrypted communication with the locking system manufacturer's computer 304 via, for example, a modem connection 208, as discussed in more detail below.

The distributor software uses a key / lock register as a module that describes the customer's system. In this way, the distributor can work transparently, as if the distributor and customer software are one system. This is essential for the distributor if it is to be closely associated with the customer system.

Authorization key for the manufacturer

A manufacturer authorization key (M-key) 302 is provided for the locking system manufacturer.

Manufacturer's programming box

Also on the manufacturer's side, the programming box 306 is similar to the distributor programming box 206 and adapted for connection to a computer (PC) 304.

Software manufacturer

The manufacturer has access to a personal computer 304 that operates with full authorization software (M-software) for key adding and deleting operations.

Information elements

All keys and locks have a unique electronic identity or code comprising several information elements controlling the function of the keys and locks. These key or lock information elements will now be described with reference to Figs. 3a and 3b, respectively.

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The electronic code is divided into different segments for use by manufacturers, distributors and customers. Some public elements are common to MKS devices, and a secret information segment is also created that is always individual to the group.

Each electronic key code includes the following parts:

• public key identification (PKID) including • manufacturer identification (M) • master key system (MKS) identification • function identification (F) • group identification (GR) • unique identity (UID) • encryption key (K _DE s) • secret key identification (SKID) including · secret group identification (SGR)

Also, each electronic lock code includes the following Parts:

• Public lock identification (PLID) including • Manufacturer identification (M) • Master key system identification (MKS) • Function identification (F) • Group identification (GR) • Unique identity (UID) • Encryption key (K _DES ) · Secret identification keys (SLIP) including • secret group identification (SGR)

The basic elements of the codes will now be described in more detail, so M - the manufacturer

M identifies the master key system manufacturer. Therefore, each manufacturer 300 utilizing the present invention is assigned a unique M-code identifying keys and locks originating from that manufacturer.

MKS - master key system

The MKS identifies different customer master key systems 100. The lock will accept a user key or a C-key only if these elements have the same MKScode.

F - function

F identifies the role of the device, i.e. whether it is a lock, a user key, a C-key, a D-key, an M-key, and so on.

GR - Group

GR is an integer identifying a group of devices, GR is unique in each MKS and starts with a number of 1 and then always increments of 1.

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UID - unique identity

The UID identifies different users in the group. The UID is unique in each group, starting with Number 1 and then always increment 1. The combination of the group identifier and unique identity thus uniquely identifies the device in the MKS.

K _DES - encryption key

Somewhere includes a randomly generated encryption key. In a preferred embodiment, the DES coding algorithm is used, partly because of its speed, and preferably a triple DES algorithm (3DES). There are several modes of operation of DES coding, two modes being advantageous for the present invention: ECB (electronic code writing) and CBC (encryption block chaining).

Where is the same on all master key system devices.

Kqes ^{is not} readable from the outside and is only used by algorithms executed inside the key and lock device. This is a very important feature because it excludes the possibility of copying a key by reading the contents of its memory. In addition, K _D es is only present in function mode keys, see discussion in the description below and protected mode.

Where is it used in authorization processes between different devices. In order for the key to be able to work with the lock, both the key and the lock must have the same Kdes · Otherwise, the authorization process is not successful.

SGR - secret group

SGR is a randomly generated number that is the same for one group. The aforementioned information elements as well as other electronic data information used in the key and lock system of the present invention are, of course, information essential to the operation of the system.

Therefore, to ensure data integrity, MAC (message verification code) seems to be used for some. In a key or lock device, the MAC is used for each authorization statement in the chip using Kdes * The MAC is also used for some data elements before the device is put into operation mode (see below) and also for some other data elements. In C-software, D-software, or M-software, the MAC is used for some uncoded data files.

The key and lock system of the present invention exhibits a very high level of security. The security architecture is based on the fact that a system key, that is, a C-key, a Key or an M-key, can work with many different software. Therefore, it is not easy to change the authentication encryption key for each authentication performed. The typical information flow in the hierarchical system shown in Figure 2 is illustrated in Figure 4. This figure illustrates, for example, the complexity of the system and the information exchanged between different levels, ie, manufacturer, distributor and customer.

In the example shown, customer 100 wishes to add a user key to his master key system (step 401). Using the scheduling software (at step 402), information regarding the desired changes is transmitted to the manufacturer via, for example, modem connections 108 and 308, see Fig. 2. accessing the M-software database (step 404) by using the M-key (step 405). The M-software database is then updated and the relevant information is sent to the D-software (step 406). for example, via modem connections 308 and 208.

At the distributor 200, the D-software database at the computer 204 is accessed (step 407) and the database is updated using the D-key 202 (step 408). A protected mode device belonging to the respective MKS is created and this device is programmed using the D-key

2 02 and programming boxes 206.

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At customer side 100, the C-software at computer 104 receives information from the distributor (step 409), for example, via a modem connection. The C-software database is accessed (step 410). this database is updated and the new device is supplied by the distributor (step 411), which is programmed through the programming box 106 and the C-key 102 (step 412). When this protected device has been put into operation mode (step 413), the M-software in the computer 304 is notified and the M-software database is updated accordingly.

The reader can easily see the complexity of all these operations and the need for a simple yet secure way to transmit electronic information as well as the key or lock device itself. Protected mode

To solve the problem of safely delivering the device to, for example, a customer or a distributor, a feature of the lock and key device of the present invention is the so-called protected mode. Essentially, this means that users at different levels of the hierarchy, ie manufacturer, distributor and end user, have full control over the authorization of devices belonging to the system.

This is done using a variable coding key stored in the electronic code of the device. The operation of this variable coding key will be described in the following description with reference to Figs. 5a to 5e, which illustrates the contents of the electronic code stored in the electronic memory of the device.

First, a device blank is formed at the manufacturer, i.e., a device without mechanical or electronic coding. The electronic code memory is thus empty, see Fig. 5a.

The next step at the manufacturer is to add the manufacturer-specific code element, see Figure 5b. This code element, labeled "M", identifies a specific manufacturer and is unique to each manufacturer. It is thus possible by simply reading the code element M to find out from which manufacturer the key (or lock) originates.

The element labeled "K _DES _ _M " is the DES encryption key used by the manufacturer M as a transport or storage code. As already mentioned, the encryption key Kdes »required for a functioning device is present only in the functional mode devices, i.e. in the activated keys and locks operating in the customer's MKS 100. The _DESM key is created by the manufacturer's software (M-software) and anyone but the manufacturer having the M-software is not possible to create a blank key (or lock) with a unique key K _DES _ _M key for that specific manufacturer. In this way, the keys are protected during storage at the manufacturer because they are unusable to anyone except the correct manufacturer.

When the manufacturer of the device is to send to the distributor, an electronic code element specific to the respective distributor is added, see Fig. 5c. This element, labeled "D", identifies a specific distributor and is unique to each distributor. This element is stored in the position usually used by the MKS code.

At the same time, the coding key K _dES _ _m is replaced by the key _Kdes -d », which is a coding key unique for the respective distributor. However, in order to make this change, verification must be carried out between the manufacturer's protected key (device) and the M-key. This verification process is successful only if the manufacturer's protected device encryption keys and M-keys, i.e. K _D es-m, are identical. The Kdes-d encryption key is stored in the M-software, where it is removed after a successful verification process. Equipped with a K _DES _ _D encryption key, the device is now in distributor protected mode.

When an order is placed by the customer, either the manufacturer or the distributor, the process of putting the key (device) into the customer's protected mode is initiated as described in connection with the references

The information required for this process is then electronically transmitted from the manufacturer's software to the distributor, but not in plain text. This information, in turn, is transmitted encoded with the Kdes-d code of the distributor. For example, the Kdes-c coding key for a customer's protected-mode device is sent in the following format:

cKdes-d

Other relevant information elements, such as MKS, GR, UID, Kdes, unless Customer Protected Mode is used, K _D es-c, are transmitted coded in the same way. This information is then downloaded to the distributor's protected key (device).

In order to decode the encoded information, a validation process must be performed at the distributor. This process takes place between the protected device and the D-key in which the Kdes _D encryption keys are stored. Thus, the code elements are decoded, whereby the protected distributor device shown in Figure 5c is converted to the customer protected device as shown in Figure 5d. At the same time, the correct function code element "F" is stored to indicate the function of the device, e.g. key.

However, the device leaving the distributor cannot yet be used in the customer master key end system, i.e. not yet in functional mode. Through C-software and a C-key, the customer accepts the customer protected device and replaces the encryption key K _D esc encryption key K _DES, see Fig. 5e. Only then can the device be used in the master key system.

The C-key is usually supplied from the manufacturer directly to the customer. The term "protected customer mode" expresses the fact that no one other than the right authorized customer can use the key (device) supplied by the distributor, since the keys (device) of the locking system must be received by the system via a C-key.

The feature that a physical key, i.e. a system key, is used to change the code of another device has several advantages. First, the physical key is easy to handle. Second, this arrangement ensures system security. No one can put the device into working mode without the correct system key (such as a C-key).

In an alternative embodiment of the present invention, the distributor level is omitted. Thus, the manufacturer is responsible for the steps described in connection with Figures 5a to 5c and delivers both the device and the system key to the customer. This will not affect system security if the device and system keys are supplied separately.

Alternatively, if desired by the customer, the keys to the customer can be delivered in a functional mode, i.e. with a stored code key K _D es- This would provide a less secure system, but the possibility to omit one or more steps on the other indicates flexibility in the concept protected mode.

As already mentioned, the information element F - function element - of the electronic code determines the role of the device. This element is '0', ie undefined during storage at the manufacturer or distributor and is given a predetermined value when the key (device) is put into working mode. This value depends on the role of the key (device); that is, whether it is a lock or user key, a C key, a D-key, or an M-key. The precise manner in which this identification is performed is not relevant to the present invention.

Security of data exchange

In the following, the security aspects of data exchange between software at different levels of the hierarchy will be discussed with reference to Fig. 6. Each manufacturer-distributor, customer-producer, and customer-distributor pair has their own encryption key to provide post-security security. However, the same encryption keys are used in both directions, i.e., both from distributor to customer and from customer to distributor. All required encryption keys are stored in the appropriate software. The encryption keys are supplied with the software, but if the encryption keys are to be updated, new encryption keys encoded with the current communication encryption keys are sent from the manufacturer.

User and system keys

Each user of the system shown in Fig. 2 must be identified by the software used. For this purpose, each user has his own unique user name and belongs to one of three user categories: superuser, read / write, or read only. Different categories have different privileges and access restrictions, which will be briefly discussed below.

The superuser category can change user rights and ownership of system keys. It can also change the password and PIN of all system keys and users and change the C-key authorization in the software. In addition, this category can perform all operations allowed by the user in the Read / Write category. To gain access to the software, the superuser needs a special system key, the so-called master system key, and must enter a PIN. There is only one master system key for each software,

The user in the read / write category can change the authorization in the MKS locking map. It can also decode and encode files for transfer to other software on the system. To access the software, a read / write user needs an authorized system key and must enter a PIN.

To access the software, a user in the Read Only category needs an MKS-related key and needs to enter a password. A read-only user can only read the locking system configuration, that is, he can follow the lock map and cannot make any changes to the authorizations, and so on.

An authentication protocol is also created between the user, system keys, and various software. The coding key K $ wipi of the software identification is stored in the software in an encoded file. This K _SW jpi coding key is unique to each system key, and the full authentication process follows the following steps: First, public identities are exchanged between the software and the sys35 theme key. The user then enters the user name and PIN. The software then verifies the authenticity of the system key in a manner similar to that described in the chapter Database Security 'below, using the above-mentioned unique software identification coding key.

Database security

In the following description, aspects of database security will be discussed with reference to Figs. 7 and 8, which illustrate the coding of the database used with the system shown in Fig. 2.

In one ICS, different information items are stored in different files. This means that if the encryption key is corrupted, only part of the database has been corrupted. Examples of various information elements are:

• File1 - lock map • File2 - list of keys and locks with their public identity (PID) • Files

Each of these files is coded with a separate coding key, which in the example shown is denoted K _{D &} -Fb Kdb-f2, ... K _DBF1 , see Fig. 7.

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A user accessing the software will provide his / her user name and PIN (except in the case of a read-only category where a password is entered instead). The user also uses the system key and the authentication process is initiated. Assuming a successful authentication process, an encryption key K _S ysj stored in the system key j used for accessing the software is used in the following decryption processes. As seen in Fig. 7, the coding key Ksysj is used in selecting the set of coded coding keys Kdb-fi, K _D b-f2, Kdb-fi, and so on, used to encode the database files 1, 2, 3, and so on. Coding keys K _DB _ _Fb

K _D b-f2 ... Kdb-f1, and so on, are thus stored themselves coded with the coding key Ksysj and are decoded by the coding key stored in the authorized physical system key.

To read, for example, the decrypted key K _D b-fi is used to decode the information stored in the database. However, in order to further enhance security, this file encryption key is modified each time a file is accessed. This is done by means of the modifier R _D b-1, see Fig. 7 and Fig. 8. The current coding key used to decode a particular file is called K _D B-Fi-n d = K _DB _ _Fi + R _D b Each time a file i is stored, a new Rdb-ϊ is calculated. This file i is encoded with a new K-DB-Fi-mod and a new one is stored in plain form.

It is important that the encryption keys used are not stored for an unnecessarily long period of time.

Thus, as shown in Fig. 7, the data elements indicated in block A are stored only in the primary memory and not on the disk. The data elements and information files indicated in block B in FIG. 7 are stored on the disc. This solution ensures safe storage of the key database because the encryption keys exist on the computer only as long as it is turned on. For example, if a computer with a database is stolen, there is no danger that decoding keys will be present in the computer system.

Identification procedure

When the key is inserted into the lock, the identification procedure is initialized. This cedura identification identifier is based on the use of coded keys and is further described in the co-pending patent application

SE-9901643-8, which is hereby incorporated by reference. However, an important feature of this procedure is that two devices communicating with each other must have the same encryption key for the process to be successfully executed, such as the authentication process.

Preferred embodiments of the present invention have been described above. One of ordinary skill in the art will readily appreciate that the locking device of the invention may be varied without departing from the scope of the invention as defined in the appended claims. For example, while the DES coding algorithm has been described in connection with the preferred embodiments, other coding techniques may be used as well.

Claims (11)

PATENT CLAIMS A method of authorizing a user equipment of a key and lock system, the user equipment being a user key (101) or a lock (20) of the master key system (100), the method comprising the following steps: - creating a user equipment (UD1) having electronic circuitry, - creating a first system device (SD1) having electronic circuitry and used in the first level (level 1) of the key and lock system, and storing the first encryption key in the first user equipment and the first system device, characterized in that it comprises the steps 15 - performing an authentication process between the user equipment and the first system device using the first encryption key, and - if the authentication process has been successful, performing a software operation by the first system device in which the first encryption key stored in the user equipment is replaced by the second encryption key, 20 - wherein the second encryption key is stored in the second system devices (SD 2) and other user equipment (UD2, UD3) used in the second level (level 2) of the key and lock system, thereby making the user equipment operable with the second system and other user equipment. The method according to claim 1, characterized in that during the step of replacing the first coding key stored in the user equipment, the second coding key is supplied by the first system device (SD1). The method of claim 1, wherein during the first replacement step 30, the second encryption key stored in the user equipment is supplied by the computer (C1). The method of claim 3, comprising the additional step of delivering a second encryption key to the computer (C1) over a network such as a local area network and a public telephone network. Method according to any one of claims 1 to 4, characterized in that the first system device is a system key of a master key system. Method according to any one of claims 1 to 5, characterized in that it is user-friendly The device is a user key (101) of the master key system (100), Method according to any one of claims 1 to 5, characterized in that the user equipment is a lock (20) of the master key system (100). 45 Method according to any one of claims 1 to 7, characterized in that the electronic coding keys are illegible from the outside of said electronic circuits. 9. A key and lock system comprising: - a number of user establishments (UDI - UD3) including: 50 - a plurality of user keys having electronic circuitry comprising an electronic memory adapted to store a variable electronic encryption key, and -12GB 3U155G B6 - a plurality of locks having electronic circuitry comprising an electronic memory adapted to store a variable electronic encryption key, - the user key and the lock being operable together only if identical encryption keys are stored in the user key and the lock, 5 comprising - at least one system device (SD1 to SD3) having electronic circuits comprising an electronic memory adapted to store a permanent electronic encryption key, and computer software adapted to change the user equipment variable electronic coding key from the first coding key to the second coding key as a result of 10 of the successful verification process performed between a lock or user key having a stored variable electronic encryption key, and - a system device having the same encryption key as said lock or user key, Wherein the second coding key is stored in second system devices (SD2) and user devices (UD2, UD3) used in the second level (level 2) of the key and lock system, thereby making the user devices operable with these second system and user devices.